The present proposal focuses on the medication adherence behaviors of rheumatoid and osteoarthritis patients. Although available medications cannot cure either form of arthritis, they do slow disease progression, decrease pain, and may even prevent disability. Thus, adherence behaviors are important to understand. Estimates of nonadherence to medications for arthritis patients are alarmingly high- as much as 60%. Until the recent advent of microelectronic monitoring devices, the measurement of adherence behaviors was unreliable and based on verbal estimates or pill counts. In addition to problems with unreliable measurement, little attention had been paid to the relationship of cognitive ability factors to nonadherence. This is surprising, because it is likely that problems in understanding and remembering a medication regimen contribute to nonadherence, particularly in elderly adults who may experience age-related declines in comprehension and memory processes. The general goal of this proposal is to understand the contribution of age-related comprehension and memory problems to medication nonadherence and to determine effective forms of cognitive interventions to improve adherence. The specific aims of the proposal are as follows: (1) Novel microelectronic devices will be used to record adherence behaviors accurately in arthritis patients for the first time and compared to more traditional measures. (Year 1-2); (2) A complete theoretical framework for understanding adherence behaviors in rheumatoid and osteoarthritis patients will be developed, using the model proposed by Leventhal and Cameron (1987). The model will focus on cognitive ability variables in addition to variables suggested by Leventhal and Cameron which include age, patient beliefs, social support and disease factors, using structural equation models (Years 3-5). (3) A range of cognitive prostheses or interventions will be developed and tested that are designed to (a) improve comprehension of medication information; (b) provide memory support for the medication information; (c) provide prospective memory assistance--remembering to take medication at the right time (Year 3-5). (4) Detailed, specific adherence data will be collected for two months from each subject, which will permit the description of nonadherence patterns, the differentiation of these patterns for drug type, disease state, dosage schedules, as well as the relationship of these valuables to cognitive ability variables and belief variables--information of great use to practicing clinicians (Year 3-5). (5) Finally, the relationship between adherence to a medication regimen and subjective well-being for rheumatoid and osteoarthritis patients will be investigated directly (Year 2-3)--an important but neglected topic.